Serendipity played a role in the development of a new diagnostic system that’s being used to detect high-risk prostate cancers in two pilot studies underway in Ontario and Saskatchewan. Dr. Hon Leong (pictured), a scientist at the Lawson Health Research Institute, has repurposed a machine that was used to detect airborne pathogens in the second Gulf War. Called a nanoscale flow cytometer, it’s now being used to conduct non-invasive fluid biopsies to detect prostate cancer microparticles. These are essentially garbage shed by prostate cancer cells into the blood.
This is the first clinical cancer research project to correlate the number of microparticles in the blood to the risk of having prostate cancer – the more microparticles, the higher the risk.
Leong stumbled across the Gulf War machine at an auction by simply googling some keywords related to flow cytometers, which are devices that most hospitals and laboratories use to analyze whole blood cells.
“What I really needed for my project was a similar machine that could analyze even smaller cell fragments.
During my whole PhD, I’d always hoped someone in the medical world would develop a machine that could analyze things that small. The one I found online was originally used to sample the air during the Gulf War to detect bioterrorism threats before any land troops entered the area. We had convoy trucks with these devices all over the Gulf War area. Here I am 15 years later, using it for something completely different.”
Using the Gulf War machine, or nanoscale flow cytometer, Leong has developed a blood test that essentially detects prostate cancer fragments. It provides a more accurate and less invasive testing method that is particularly helpful in identifying high-risk patients as an alternative to relying on inconsistent PSA scores or painful biopsies.
“The accuracy rate of our test is about 85 percent based on preliminary testing, and we’re doing two big clinical studies in Ontario and Saskatchewan to get more data. We are currently at Phase 2 validation for medical devices, and the focus of our test is strictly on identifying high-risk prostate cancer.”
A useful feature of the testing protocol is that the blood sample doesn’t need to be preserved, he adds. “We’ve been able to analyze frozen samples quite readily and still get the same results. The test is quite robust in that we’re not dependent on the blood expiring before it gets to us for analysis. So you don’t have to worry about refrigeration or transporting it instantly.”
The Saskatchewan study is being conducted with the help of the Saskatchewan Cancer Agency, which is the only organization in Canada that provides free screenings. “We’ve obtained 2,000 serum samples, and we don’t know who has cancer or not because this is a prospective study. We’re going to use our test to identify which patients have cancer and then follow-up a year later to determine which of those patients actually develop high-risk prostate cancer via the normal conventional means – rectal exam and biopsies.”
In the Ontario study, Leong and his team will be monitoring men who already have low-risk prostate cancer. Men in this category have about a 30 percent risk of having their disease evolve to a more aggressive form.
“We usually defer surgery unless it’s absolutely necessary for the majority of men with low-risk prostate cancer. To monitor them, we have to rely on needle core biopsies of the prostate performed every year to find out if these men are developing a more aggressive form of the cancer over time. It would be great to have a non-invasive way to determine if the cancer gets worse. So we want to see if these patients can rely on our test instead of undergoing a painful biopsy every year.”
Leong and his team hope to get Health Canada and FDA approval very soon for their low-cost prostate cancer blood test. “I believe the timeline for this will be at most 5 years, but it could easily be ready even sooner, in 3 years, given the rate at which we’re doing all these tests.”
The test has the potential to make dramatic changes in the way men are screened for prostate cancer.
“Right now, there is no screening for prostate cancer. Ever since the recommendations were made against PSA testing by American and Canadian task forces, we’ve actually seen an increase in the number of men who present with high-risk prostate cancer. So we need something to replace PSA, and we think our test is it.”
The benefit of this kind of blood test would be that doctors need only look for high-risk prostate cancer, which is the only clinically relevant form, says Leong. “The low risk or even the intermediate risk, we actually don’t even need to really act on those prostate cancers. So using this kind of assay to only identify those men in a large population setting is probably what we need the most.”
The test could also restore faith in public health. “Right now, when we use PSA, the false-positive rate is just too high. It carries a significant burden because a lot of these men don’t even need biopsies and they suffer a lot of serious anxiety when it turns out that the PSA was wrong and the biopsy was unneeded in the first place.”
For more information, visit https://www.lawsonresearch.ca/media-releases